The present invention relates in general to filter units, and, more particularly, to fuel filter units.
Ideally, there should be little or no water present in the fuel used to operate an internal combustion engine. However, it is extremely difficult to remove all water from such fuel, and eventually the cost of removing such water exceeds the benefits derived from such removal.
Internal combustion engines can operate on fuel containing small amounts of water; however, as above-discussed, there is an upper limit of water content whereat the engine will no longer operate or will be subject to damage by such water-containing fuel. At such point the engine should be shut down as quickly as is safely possible.
This above-discussed problem has engendered many devices meant to prevent water-containing fuel from reaching internal combusion engines. Examples of these devices are disclosed in U.S. Pat. Nos.: 3,385,440, 3,542,194, 4,053,405, and 4,132,646.
While effective, the devices disclosed in the above-cited patents have several drawbacks. Principal among these drawbacks is the inability of these devices to be adapted for use in flow situations wherein the fluid being filtered flows through the filter unit in turbulent flow or in transition flow conditions. Furthermore, these devices must be oriented vertically to work, and there is still a distinct possibility of water bypassing the blocking means, especially when the water level approaches the level selected as the maximum allowable level.